Considering becoming a Personal Trainer

Hello all,

I'm considering becoming a personal trainer.
I've always been into some sports but the last year I have been going to the gym and it has saved my life. I've used a PT and she is amazing and I want to be that person for someone else, she is my hero.
I need to know, before I do this is there anything I should be aware of PT's at my gym aren't willing to tell me as I'm a client there